This invention relates to the compensation of parasitic or unwanted capacitance in capacitance measurement applications.
Methods of using capacitance measurement to detect the proximity and/or vicinity of an object are known in the art. Inherent parasitic capacitances associated with sense plates, switches, connections and wiring degrade performance in these applications. The same holds true for other capacitance measurement applications. A specific capacitance measurement technique of importance is the “charge transfer method”.
This invention aims to provide a technique to compensate for these parasitic capacitances and thus improve performance.
The invention also relates to an embodiment of the charge transfer method that overcomes the effect of non-linearity in a charging capacitor and enables scaling of a capacitor so that the method can be implemented practically and economically on standard CMOS integrated circuits.